Portal:Australia/Anniversaries/March/March 21
- 1918 – The Australian Corps commences fighting to stop the German offensive Operation Michael, the German advance near Amiens.
- 1931 – The ANA aircraft Southern Cloud, carrying eight persons, disappears on a flight between Sydney and Melbourne. The wreckage is not located until 1958.
- 1963 – At a special federal conference of the Australian Labor Party, Arthur Calwell and Gough Whitlam were photographed outside the venue at Kingston in Canberra. Although Calwell was the Leader of the Opposition, neither man was a member of the federal executive. Robert Menzies jibed that the ALP was ruled by "36 faceless men".
- 1975 – Malcolm Fraser replaces Billy Snedden as leader of the Liberal Party of Australia.